Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 68 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Support/UniqueLock.h b/clang-r353983/include/llvm/Support/UniqueLock.h
new file mode 100644
index 00000000..0a887ad5
--- /dev/null
+++ b/clang-r353983/include/llvm/Support/UniqueLock.h
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+//===- Support/UniqueLock.h - Acquire/Release Mutex In Scope ----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a guard for a block of code that ensures a Mutex is locked
+// upon construction and released upon destruction.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SUPPORT_UNIQUE_LOCK_H
+#define LLVM_SUPPORT_UNIQUE_LOCK_H
+
+#include <cassert>
+
+namespace llvm {
+
+  /// A pared-down imitation of std::unique_lock from C++11. Contrary to the
+  /// name, it's really more of a wrapper for a lock. It may or may not have
+  /// an associated mutex, which is guaranteed to be locked upon creation
+  /// and unlocked after destruction. unique_lock can also unlock the mutex
+  /// and re-lock it freely during its lifetime.
+  /// Guard a section of code with a mutex.
+  template<typename MutexT>
+  class unique_lock {
+    MutexT *M = nullptr;
+    bool locked = false;
+
+  public:
+    unique_lock() = default;
+    explicit unique_lock(MutexT &m) : M(&m), locked(true) { M->lock(); }
+    unique_lock(const unique_lock &) = delete;
+     unique_lock &operator=(const unique_lock &) = delete;
+
+    void operator=(unique_lock &&o) {
+      if (owns_lock())
+        M->unlock();
+      M = o.M;
+      locked = o.locked;
+      o.M = nullptr;
+      o.locked = false;
+    }
+
+    ~unique_lock() { if (owns_lock()) M->unlock(); }
+
+    void lock() {
+      assert(!locked && "mutex already locked!");
+      assert(M && "no associated mutex!");
+      M->lock();
+      locked = true;
+    }
+
+    void unlock() {
+      assert(locked && "unlocking a mutex that isn't locked!");
+      assert(M && "no associated mutex!");
+      M->unlock();
+      locked = false;
+    }
+
+    bool owns_lock() { return locked; }
+  };
+
+} // end namespace llvm
+
+#endif // LLVM_SUPPORT_UNIQUE_LOCK_H